U.S. Pat. No. 6,823,283 to Steger, et al., describes a measurement device. The measurement device is comprised of one or more measurement modules or cards inserted into a carrier unit. The carrier unit is a “chassis” or “card carrier” such as the NATIONAL INSTRUMENTS (“NI”) PXI-1031 PXI Chassis. The measurement modules are sometimes data acquisition (“DAQ”) modules such as the NI PXI-4220 module, or other modules such as digitizers, digital multimeters, scopes, or arbitrary waveform generators.
The chassis can also include a NI PXI-8184 Celeron-Based Embedded Controller for controlling the measurement modules. Alternatively, an external personal computer (“PC”) can be used to control the modules.
Included in the chassis is a backplane providing electrical communication with the measurement modules. The chassis can be a PXI standard chassis and the backplane can be a PXI standard trigger bus.
The problem is that the cost of the system, even without any measurement modules, is already around US$3000 (all prices are in year 2006 dollars), and after adding measurement modules can be well over US$5000.
Low cost stand-alone measurement devices are also commonly available. For example, EasySync Ltd. of Glasgow, and NATIONAL INSTRUMENTS both provide USB measurement devices, such as Oscilloscopes and DAQs for around US$200 or less. These measurement devices plug directly into a PC and are controlled using the USB standard.
Often, those with limited budgets will first purchase the less expensive stand-alone measurement devices. However, if they later need to perform more complicated DAQ, measurement, or control applications, the purchase of the stand-alone measurement devices will have been a waste and they will need to start from scratch by purchasing a new high-priced chassis and several new high-priced chassis-based measurement devices.
It would be beneficial if the same measurement modules could be used in multiple configurations in both stand-alone configurations and in chassis mounted configurations